Abstract

The wave processes in a rotating layer of compressible astrophysical plasma with a stable stratification and a linear entropy profile are studied theoretically. The compressibility is taken into account in the anelastic approximation. In this approximation the acoustic waves are filtered out, the system contains terms with a potential temperature (entropy), and the continuity equation contains an initial stratified density profile. The Coriolis force in the magnetohydrodynamic equations for a compressible astrophysical plasma is considered in four different approximations: a traditional f-plane, a nontraditional f-plane (given the horizontal component of the Coriolis force), a traditional β-plane, and a nontraditional β-plane. Linear and nonlinear theories of wave processes have been developed for each Coriolis force approximation under consideration. New types of waves have been found, with the rotation, magnetic field, gravity, and compressibility serving as their restoring mechanisms. The compressibility effects are represented in the new dispersion equations by the Brunt–Väisälä frequency for compressible stratified flows dependent on both initial density and pressure profiles. All of the realizable types of three-wave interactions have been revealed through a qualitative analysis of the dispersion curves. A system of equations for the amplitudes of interacting waves and the growth rates of parametric instabilities have been derived by the multiscale expansion method.

中文翻译：

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具有稳定分层的可压缩天体等离子体流动的波动过程

摘要

理论上研究了分层稳定且线性熵分布的可压缩天体等离子体旋转层中的波过程。在非弹性近似中考虑了可压缩性。在这种近似中，声波被滤除，系统包含具有潜在温度（熵）的项，而连续性方程则包含初始的分层密度分布。在磁流体方程科里奥利力为可压缩等离子体天体物理学在四个不同的近似值被认为是：传统的˚F -平面，非传统˚F平面（考虑到科里奥利力的水平分量），传统的β平面和非传统的β平面。对于考虑中的每个科里奥利力近似，已经开发了波动过程的线性和非线性理论。已经发现了新型的波，其中旋转，磁场，重力和可压缩性是它们的恢复机制。可压缩分层流的Brunt–Väisälä频率在新的弥散方程中表示可压缩性，这取决于初始密度和压力分布。通过色散曲线的定性分析，揭示了所有可实现的三波相互作用类型。